Is UML still seen as a viable way of documenting a software design?

IMO, UML lost much of its image as the only-and-always-best solution for software development. While enthusiasts in the beginning are (and some still are) in the opinion that UML will solve design problems and everything should ideally be drawn with UML. Reality proved that it is not much better then any other kind of diagram.

IMO, UML is now widely seen as what it actually is: a standard for many diagrams needed in oo analysis and design. It is indeed the most popular diagram standard in use. There are more tools around and more people know UML then any other diagram style.